Submission #1034714

#	Time	Username	Problem	Language	Result	Execution time	Memory
1034714		vjudge1	Pipes (CEOI15_pipes)	C++17	40 / 100	166 ms	19796 KiB

pipes

#include <bits/stdc++.h>
using namespace std;

const int N = 30'010;
struct dsu {
	int e[N];
	dsu() {
		memset(e, -1, sizeof e);
	}
	int find(int x) { return e[x] < 0 ? x : e[x] = find(e[x]); }
	bool sameSet(int a, int b) { return find(a) == find(b); }
	bool join(int a, int b) {
		a = find(a), b = find(b);
		if (a == b) return false;
		if (e[a] > e[b]) swap(a, b);
		e[a] += e[b]; e[b] = a;
		return true;
	}
} d1, d2;
vector<int> g[N+1];
int low[N+1], id[N+1];
int timer=0;
void dfs(int at, int par) {
	bool ck=0;
	id[at]=low[at]=++timer;
	for(int to:g[at]) {
		if(to == par and ck==0) {
			ck=1;
			continue;
		}
		if(id[to]) {
			low[at]=min(low[at], id[to]);		
		} else {
			dfs(to, at);
			low[at]=min(low[at], low[to]);
		}
	}
	if(low[at] == id[at] and at!=par) {
		cout << at << " " << par << "\n";
	}
}
int main() {
	cin.tie(0)->sync_with_stdio(0);
	cin.exceptions(cin.failbit);
	int n, m;
	cin >> n >> m;
	int u, v;
	int cnt=0;
	for(int i = 0;i<m;i++) {
		cin >> u >> v;
		if(d1.join(u, v) || d2.join(u, v)) {
			g[u].push_back(v);
			g[v].push_back(u);
		}
	}
	for(int i= 1;i<=n;i++) {
		if(!id[i]) {
			dfs(i, i);
		}
	}
}

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:48:6: warning: unused variable 'cnt' [-Wunused-variable]
   48 |  int cnt=0;
      |      ^~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10